/Engine/Source/Editor/GraphEditor/Public/GraphActionNode.h
Recursively collects all decendent action/separator nodes (leaves out branching category-nodes).
void GetLeafNodes ( [TArray](API\Runtime\Core\Containers\TArray)< [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FGraphActionNode](API\Editor\GraphEditor\FGraphActionNode) > > & OutLeafArray ) const